Refrigerating apparatus



July 19, 1938. H, M wlLLlAMS 2,124,268

REFRIGERATING APPARATUS Filed Aug.v 31, 1931 2 Sheets-Sheet 1 ATTORNEY 2 Sheets-Sheet 2 INVENTOR M ww M3 1 ATTORNEY 1 WWW 7 an E We a H. M. WILLIAMS REFRIGERATING APPARATUS July 19, 1938.

Patented July 19, 1 938 nnrmesaarnve APFABATUS Harry M. Williams, Dayton, Ohio,- assignor, by

mesne assignments, to General Motors Corporation, a corporation of Delaware Application August 31,

7 Claims.

This invention relates to refrigerating apparatus of the type which includes a cooling element adapted to be placed in the path of a cooling medium and which is adapted to be maintained normally at a temperature causing solidification of a part of said medium flowing thereover and more particularly to improved means for quickly removing the solidified medium accumulated on said cooling element.

One of the objects of this invention is to provide improved means for freeing the cooling element from frost and iceaccumulated thereon.

More specifically it is an object to provide a refrigerating cabinet with a cooling element for 5 cooling food articles stored in said cabinet and to arrange said cooling element in such a manner whereby circulating air within the cabinet is circulated over said cooling element and to. arrange said cabinet and cooling element in such 20 a manner so that said element may be exposed to a medium of a higher temperature than the circulating air within the cabinet for defrosting said element. In practicing this invention it is a further object to utilizethe warm air outside 25 of the refrigerating cabinet and circulate said warm air over the cooling. element for defrosting said element while at the same time preventing said warm air from entering the food storage compartment of the refrigerating cabinet.

30 Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

35 In the drawings:

Fig. 1 is a diagrammatic illustration of a refrigerating apparatus embodying features of the invention;

Fig. 2 is an enlarged viewof a portion of the 40 apparatus shown in Fig. 1 and showing a modified arrangement for controlling the operation of therefrigerating apparatus;

Fig. 3 is a diagrammatic illustration of a modified form of refrigerating apparatus embodying 45 features of the invention;

1931, Serial No. 560,279 (01. 62-115).

element which usually operates automatically in response to normal conditions within the appa ratus to chill the cooling element and induce the circulation of air in the space to be cooled. This cooling element soon becomes coated with frost 5 and ice formed by the freezing of water con-. densing on the cooling element from the circu-' .lating air and this frost and ice forms a resistance to the transfer of heat from the air to the cooling element and thus reduces the efficiency 10 of the system. Since the refrigerating requirements of the cabinet vary from time to time and since refrigeration is produced by the apparatus at a substantially uniform rate, which rate must be slightly higher than the maximum requirement of the space to be cooled, it is usual to operate the refrigerating system intermittently in order to prevent cooling the space below the desired temperature.

In practicing this invention it is a further object to prevent operation of the refrigerant circulating element in response to normal conditions within the apparatus when it is desired to defrost the cooling element. This is accomplished in a manner hereinafter described.

Referring to the drawings, and particularly to Figs. 1 and 4, the numeral 20 designates in general a refrigerator cabinet embodying features of my invention. The cabinet 20 includes an insulated shelf 2|. The shelf 2| divides the cabinet into a food storage compartment 23 and a compartment 24 in which is disposed a cooling element or evaporator 26.

The evaporator 26 is formed of a continuous coil of pipe and is supported upon supports 28 in the compartment 24. Liquid refrigerant is supplied to the evaporator through a liquid conduit 30 under the control of a pressure responsive expansion valve 3| which increases the flow of refrigerant to the evaporator as the pressure therein decreases and decreases the flow of refrigerant to the evaporator as the pressure therein increases. vaporized refrigerant is vwithdrawn from the evaporator through a vapor conduit 32, both conduits 30 and 32 being suitably connected to a refrigerant circulating element 35. The element 35 includes a condenser 31', receiver 38, to which the conduit 3|! is connected, a compressor 40 and a motor 42 for drlving the compressor. The motor is supplied with current through the power mains 45 under the control of; an automatic switch 41. The switch 4'! is actuated by means of a thermostat 48 disposed in the compartment 23 and responsive to the temperatures therein for actuating said switch for starting and stopping the motor 42.

In order to provide for the proper circulation of air within the cabinet 20, I have provided a fan 52 which is driven by electric motor 54. The motor 54 is connected directly across the power mains 45 and is preferably operated continuously. However, if desired, any suitable switch may be placed in the circuit to the motor 54 for interrupting the flow of current thereto. The air within the compartment circulates or passes from the compartment 24 through an elongated opening 56, flue 58 and into compartment 23 and is returned to the compartment 24 through an elongated opening 51. Thus, it will be apparent that the fan 52 will force the air over the cooling element 26 through opening 56 into compartment 23 whence it returns to compartment 24 through opening 51 to be recirculated by fan 52.

In many instances the cooling element 26 is employed to maintain frozen food articles in a frozen condition and consequently to maintain the temperature of the storageor display compartment in which they are stored below the thawing point of such articles. Moisture from the foods and from the air is condensed and frozen on the cooling element, which frozen moisture or frost insulates the element. For this reason it is desirable to defrost the evaporator occasionally and such defrosting should be done" quickly in order to prevent the temperature of the food storage compartment from rising above the thawing point of said articles.

In accordance with this invention, I provide means for quickly defrosting the cooling element and for sealing the food storage compartment against the warming effect of defrosting. This means comprises utilizing the warm air on the outside of the cabinet 20' and circulating the warm air over the cooling element 26 by means of fan 52. provided doors 60 and BI located at opposite ends of the compartment 24. Doors 60 and GI normally close openings 63 and 64 respectively. These doors are arranged to be swung inwardly for admitting outside air into the compartment 24 and I have also arranged these doors so that they will seal the openings 56 and 51 to prevent the warm air in the compartment 24 from entering the food storage compartment 23. In order to prevent operation of the refrigerant circulating element when it is desired to defrost the cooling element 26, I have provided a switch 65 which may be opened to interrupt the circuit to the electric motor 42. If desired, an electric heating element 6'! may be placed in the compartment 24 for increasing the temperature of the air being circulated over the cooling element 26 for reducing the time required for defrosting the cooling element 26. The circuit through the heating element 6! is controlled by switch 10. As shown in Figs. 1 and 4 the food storage compartment 23 is provided with a plurality of shelves 12 preferably of the open-work type adapted to support food In order to accomplish this, I have during defrosting periods from warming up the compartment 23.

From the foregoing it will be noted that I have provided a refrigerating cabinet for the storage and display of food articles and that I have arranged said cabinet and cooling element in such a manner that the cooling element may be readily and quickly defrosted without interfering with the temperaturessought to be maintained in the food storage compartment to any material extent. It will also be noted that I have accomplished this by utilizing the warm air outside of the refrigerator cabinet for defrosting the cooling element and I have arranged for preventing said warm air from entering the food storage compartment. It will also be noted that the electric fan 52 is preferably operated continuously for circulating the cool air through the compartments 23 and 24 or for circulating the warm air from the outside of the cabinet over the cooling element at defrosting periods. Furthermore, it will be noted that I have provided auxiliary means for increasing the temperature of the air being circulated over the cooling element during defrosting periods.

Referring now to Fig. 2, it will be noted that I have provided a modified form of control for the refrigerating apparatus. In this embodiment I have provided a control apparatus 80 which comprises movable levers 8| and 82 which actuate movable contacts 83 and 85. This control apparatus 80 is arranged to be actuated by roller 81 carried by door 60. As shown in the drawings the circuit through the motor 42, which drives compressor 40, is closed and the circuit through the motor 54 which drives fan 52 is also closed while the circuit to the electric heater 6'! is open. When it is desired to defrost the cooling element 26, the door 60 is moved inwardly and in so doing the roller 81 engages lever 82 to move the contact member 83 downwardly to engage stationary contact 94 to thereby close the circuit to the electric heater 61. When this movement of the control apparatus 80 takes place, the movable contact member 85 is separated from stationary contact member 88 to thereby interrupt the circuit to the electric motor 42 to render the refrigerant circulating element inoperative at this time. As shown in Fig. 2, the roller 81 is adapted to engage a member 91 carried by the insulated shelf 2| to hold the door 60 in the position shown in dot and dash lines in Fig. 2 of the drawings. The member 91 is preferably resilient to provide a sufficient frictional connection between itself and the roller 81 to hold the door 60 in the dot and dash line position. When .the door 60 is in this position it will engage a gasket seal member 99 to seal the compartment 24 from the compartment 23. When the door 60 is being moved to close opening 63 the roller member 81 will engage the lever 8| which is at this time in a substantially vertical position to thus return the control apparatus to its position shown in Fig. 2 to thus interrupt the circuit to the electric heater and close the circuit to the electric motor 42. When this takes place, and the switch 41 has closed its contacts, the motor 42 will operate to drive the compressor to supply refrigeration to the cooling element 26. A separate switch I05 is provided for interrupting the circuit to the electric heater in the event it is desired to render the heating element ineffective. Thus it will be noted that all that is necessary in order to defrost the cooling element 26 is to move the doors 60 and 6| inwardly and that when the cooling elecontrol mechanism and cooling element.

ment 25 has been defrosted, the doors 50 and 6| may be returned to their normal position.

In Fig. 3 I have shown a modified form of In this embodiment a cabinet I20 which corresponds to cabinet 20 is employed for the storage and display of food articles which are adapted to be cooled by a cooling element generally represented by the reference character I25. The cooling element I25 is of' the flooded float controlled type and includes headers I21 and I28 forming reservoirs for liquid refrigerant the level of which I have indicated atI29 in Fig.5. The headers I21 and I28 of cooling element I25 are interconnected by a plurality of conduits I30. The liquid level is maintained substantially constant by a float valve not shown herein but fully disclosed in the patent to Osborne 1,556,108, issued October 13, 1925.

Liquid refrigerant is supplied to the cooling element through a liquid conduit I and evaporated refrigerant is withdrawn from the cooling element through a. vapor conduit I31, both conduits being suitably connected to a refrigerant circulating element I40. The element I includes a condenser I42, receiver I43, to which the conduit I35 'is connected, a compressor I and a motor I41 for driving the compressor. The

motor is supplied with current from the power instance, in response to change in pressure in the vapor conduit I31. The switch includes an expansible bellows I52 and suitable leverage mechanism I 53 pivoted at' I54.

In this embodiment I have prevented the operation of the refrigerant circulating element in response to normal .conditions within the system and have arrange for simultaneously rendering a heating element IBIla effective when it is desired to defrost the cooling element. I have also arranged for the automatic restoration of said means to its normal position in the event that certain abnormal conditions occur within the system to thus render the heating means ineffective to produce its function and to place the refrigerating element in readiness for operation. In this embodiment I have provided doors I 60 and IGI which correspond to doors 60 and GI for exposing the cooling element I25 to the outside air and for shutting off the food storage compartment from said outside air. I have also provided an electric fan I10 which is driven by electric motor I12 for circulating the warm outside air over the cooling element I30 during the defrosting periods and for circulating the cool air throughout the cabinet when the food storage compartment is being refrigerated. Preferably the motor I12 operates continuously.

As shown in Fig. 5 the heating element I600. has a portion thereof secured to and extending through the end wall of header I28 and has another portion thereof extending into the lowermost conduit I30 of cooling element I25 and said heating element is thereby immersed in the liquid refrigerant in the cooling element I25. Thus, it will be apparent that the heating element gives up its heat to the refrigerant which causes it to boil and circulate refrigerant throughout the entire cooling element. This causes the temperature of the walls of the cooling element to be increased, causing'the ice and frost to melt and drop loose from the cooling element in large chunks; It will also be apparent that the fan I10 (see Fig. 3) circulates warm air-from the outside of the cabinet over the cooling element I25 for rapidly defrosting the cooling element.

The circuit through the heating element is completed upon closure of a set of contacts I15 which takes place in a manner about to be described.

During defrosting periods of the cooling element, it is desired to render the refrigerant circulating element inoperative and in order to accomplish this, I have provided a suitable arrangement which renders the switch I ineffective to normal conditions within the system for causing operation of the circulating element, while at the same time the circuit through the electric heating element is completed. I have provided a pivoted lever I18 which moves the leverage mechanism I53 upwardly to engage the movable member of contacts I15 to close the electric heating circuit and by this upward movement of the leverage mechanism the switch is moved out of its normal operating position and is ineffective to normal pressures within the bellows I52. In order to maintain the heating circuit closed and to maintain the leverage mechanism I53 out of its operating position, I have provided a resilient locking device I80 which receives the handle end I8I. of lever I18. This locking device keeps the lever I18 locked in position during defrosting period and prevents the movement of the lever during defrosting operation. However, the lever I18 may be so arranged that when the defrosting period has been completed the pressure in the bellows will be suflicient, due to the increasedtemperature of the cooling element I25, so that it will exert suflicient pressure on the lever I53 to move the lever I18 downwardly by means of pin I90 to thus restore the leverage mechanism and switch I50 to its normal operating position. The pressure at which the bellows I52 renders the heating device ineffective and restores the switch I50 to normal operating position occurs after the cooling element has been entirely defrosted.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. Refrigerating apparatus comprising in combination, a. cabinet having a food storage compartment therein, a, cooling element for cooling the food compartment, a door for said cabinet, and electrical means controlled by said door for increasing the temperature of the cooling element to cause defrosting thereof.

2. A refrigerating apparatus comprising in combination, a cabinet having a chamber therein, means dividing said chamber into an upper cold storage compartment and a cooling element compartment disposed below said cold storage compartment, a cooling element disposed within said cooling element compartment, said means having a normally open passage therein for the circulation of air cooled by said cooling element from said cooling element compartment to said cold storage compartment, means for closing said normally open passage in said first named means to isolate said compartments from air circulation therebetween, and means for exposing said cooling element compartment to at mosphere exteriorly of said cabinet while said passage is closed to defrost said cooling element.

3. A refrigerating apparatus comprising in combination, a cabinet having a chamber therein, means dividing said chamber into a cold storage compartment and a cooling element compartment, a cooling element disposed within said cooling element compartment, said means having a plurality of normally open passages therein for the circulation of air cooled by said cooling element from said cooling element compartment to said cold storage compartment, means for closing said normally open passages in said first named means to isolate said compartments from air circulation therebetween, means for opening a plurality of sides of said cooling element compartment to atmosphere exteriorly of said cabinet while said passages are closed, and means for creating a flow of air entirely through said cooling element compartment to defrost said cooling element.

4. A refrigerating apparatus comprising in combination, a cabinet having a chamber therein, means dividing said chamber into a cold storage compartment and a cooling element compartment, a cooling element disposed within said cooling element compartment, said means having a normally open passage therein for the circulation of air cooled by the cooling efiect produced by said cooling element from said cooling element compartment to said cold storage compartment, a door for closing said normally open passage in said means for isolating said compartments from air circulation therebetween, and means controlled by said door for stopping the cooling effect produced by said cooling element to cause defrosting of same.

5. A refrigerating apparatus comprising in combination, a cabinet having a chamber therein, means dividing said chamber into a cold storage compartment and a cooling element compartment, a cooling element disposed within said cooling element compartment, said means having a normally open passage therein for the circulation of air cooled by the cooling effect produced by said cooling element from said cooling element compartment to said cold storage compartment, a door for closing said normally open passage in said means for isolating said compartments from air circulation therebetween, and electrical means controlled by said door for increasing the temperature within said cooling element compartment to defrost said cooling element.

6. A refrigerating apparatus comprising in combination, a cabinet having a chamber therein, means dividing said chamber into a cold storage compartment and a cooling element compartment, a cooling element disposed within said cooling element compartment, said means having a normally open passage therein for the circulation of air cooled by said element from said cooling element compartment to said cold storage compartment, and a single means for closing said a normally open passage in said first named means to isolate said compartments from air circulation therebetween and for exposing said cooling element compartment to atmosphere exteriorly of said cabinet to cause defrosting of said cooling element.

7. A refrigerating apparatus comprising in combination, a cabinet having a chamber therein, means dividing said chamber into a cold storage compartment and a cooling element compartment, a cooling element disposed within said cooling element compartment, said means having a normally open passage therein for the circulation of air cooled by said element from said cooling element compartment to said cold storage compartment, a single means for closing said normally open passage in said first named means to isolate said compartments from air circulation therebetween and for exposing said cooling element to atmosphere exteriorly of said cabinet to cause defrosting of said cooling element, and means rendered effective by movement of said single means for increasing the temperature within said cooling element compartment to augment the defrosting of said cooling element.

HARRY M. WILLIAMS. 

